Simple really. They could buy Wrexham for a lot less than DC would sell us for.
Also, don’t focus too much on the population of Wrexham itself. It’s the only league club in North Wales, so they have a large catchment area. They could also gain support from some of the English border towns, and being Welsh but far from south Wales, they could also become a “second team” for people down there. Unless they are playing Swansea, Cardiff, or Newport on a particular day, they might get plastics down there supporting them too.